Why Paleobiology Is Critical to our Climate Future

December 21, 2022

Humans have been on this planet for a blink in geological time. Perhaps you’ve heard the analogy that if the 4.5 billion-year history of the Earth was compressed into 24 hours, all of recorded human history would last but a few seconds before midnight. 

I’m writing to tell you that this is not the full story. By understanding more of the 23 hours and 58 minutes before our species arrived, we can comprehend why this moment in time is not just another instant; it’s a critical point of evolution, not only for our species but for the biosphere as a whole. 

First, we must clear our perceptions of geological time that stem from our limited view of the climate throughout human history. It can be tempting to view all of pre-industrialization as a kind of climatic Eden, which we as humans have corrupted, and therefore, that the Earth would be better off without us. 

The truth is far more bizarre, miraculous, and interesting. There has never been a climatic baseline on the planet. In fact, our current climate is more of an anomaly than the rule. Since the dawn of multicellular life, ice caps have covered the poles at most 20% of the time. 

Why is this important? By understanding how this 20% came to be, we can understand the highly unusual and contingent events that led to our current climate. We can see how the actions of one species, such as microscopic algae, can perturb Earth’s atmospheric CO2 levels and echo for eons. We can see patterns come into focus and understand that, after billions of years of evolution, we are again at the onset of one of these highly contingent events. We, however, have the ability to be the first organism to act intentionally to influence the outcome, thus preserving our own flourishing and that of the biosphere as a whole.

This is the pattern:
Every major ice age over geological history has been triggered by an evolution in photosynthesis.

From the simple single-celled algae that first oxygenated the world, killing 99% of life in the process (due to excessive oxygen levels), to the first trees to forest the land to the fern that iced the poles, plants have been the primary cause of major carbon drawdown events. Read more in our Deep Time series.

The Eden of our imagination is actually a history of cataclysmic extinctions, infernos, decimating ice ages, and multiple species suffocated by their own success. After each of these crises, we see a miraculous evolution in the life that regenerates: from the first eukaryotic cells to multicellular organisms to the explosion of diverse, macroscopic life we see today.

By understanding the intertwined development of our biosphere and atmosphere, we can see how life influences the conditions determining its own future evolution. Our atmosphere creates the environment that sustains the evolution of life on Earth, and only certain kinds of life are able to survive within different atmospheric conditions.

The Earth’s lifetime over billions of years has been a dance between geological forces spewing vast amounts of carbon into the air and photosynthetic organisms removing it. What is unique about our time is that humans are doing the work previously done by large volcanic eruptions: transforming carbon stored outside of our bodies into carbon dioxide gas and releasing it into the atmosphere.

Humans appropriate roughly 30% of the terrestrial biosphere to feed ourselves and produce raw materials. We’re burning ancient stores of carbon buried underground, causing carbon dioxide levels on par with the Pliocene era (3 million years ago) when temperatures were 4°C higher.

From the perspective of deep history, humans and all the species that accompany us are the leading edge of the biosphere in time, and the way we respond to the climatic consequences of our actions will write the future trajectory of life on Earth.

As we, at Living Carbon, work with plants to evolve solutions to climate change, our philosophy is that studying deep time is critical to meeting the challenge - and opportunity - of our current climate crisis. By studying deep time, we can see the power of evolution to spark highly contingent and unusual events, which force the development of ever more integrated and interdependent life forms in response. This is the process through which we can trace the causes of our own existence. If we want to survive in any meaningful capacity as a species, we can’t afford to wait for evolution to save us.  

The good news? We already have a highly contingent event on our side. We have unique, meta-cognitive abilities, the origin of which can be followed back through evolutionary time to the first simple single celled organisms who first built the Earth’s atmosphere. We are capable of causal reasoning and future planning. We have language and communication gifts hitherto unknown in the biosphere.

This is not to aggrandize humans, only to place our cognitive abilities a small step beyond the simple fern, carried on the feet of flying waterbirds, who singularly plummeted CO2 levels by 80% over a relatively brief moment in geological time [read more]. The fern happens to arrive in the perfect location at the perfect time. It proliferates and sinks to the bottom of the Arctic Ocean, locking away stored carbon and refreezing the poles. We can work with plants to help evolve solutions which mimic highly contingent ecological events. We can increase the ability of photosynthetic life to remove carbon from the atmosphere and reduce the rate of decay and return.

Our species has already assumed de facto responsibility for both geological and biological Earth cycles. Only by explicitly accepting this responsibility can we become the eyes of the biosphere awakening in intentional understanding of our own place in the great story which gave us birth.

This post was part of our Deep Time Series. Continue reading the next post: The Origin of Oxygenic Photosynthesis.

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